Preload – is an application that practically pre-loads or better still caches your frequently used applications with the aim of speeding up their load-time.
This application that works in the background deploys only unused RAM and does not consume your system memory as imagined.

On Ubuntu you can install Preload with the command

sudo apt-get install preload

or you can download the source code from SourceForge.net
The default settings are just fine.

To monitor your resources used by Preload type the command

sudo tail -f /var/log/preload.log

–This special command line displays the last few lines of the log and then monitors the file.

The graph below shows that Preload works marvels for bigger applications like OpenOffice.org, and little applications benefit less.

— This table is not a standard, on new sytems it could be quite different

Preload is recommendable for heavy app-users and for those working on slow systems. Since Preload is a daemon that starts at boot-up it also reduces the Login Time. On my system (A Sony Vaio, Pentium IV, 512Mb Ram, Ubuntu 7.10) it reduced the login time by roughly 8 seconds.
via [Techthrob.com]